As a member of a species that generally doesn’t swallow the afterbirth or eat feces, I feel qualified to discuss the fact that some dog behavior grosses humans out. I was thinking about this recently as I raced to my refrigerator for a piece of cheese to use to encourage a dog to drop the tissue that had fallen from my pocket as I reached for my lip balm. He was attempting to chew the tissue (used, of course) and while many a dog has eaten tissues with no ill effects, it’s not generally considered health food. Luckily, the cheese was more appealing, so I was able to convince him to drop the tissue so I could put it into the trash bin where it belonged.

Dogs do other disgusting things besides the rather mild eating of used tissues. If people had any idea how often clients had confided in me that their dog had taken a discarded tampon from the garbage and ran through the house with it (invariably in front of company), you’d be amazed. This is common behavior in dogs, and the fact that we humans find it revolting does not make dogs any less likely to do it.

The same goes for rolling in the poop of other animals. Fox poop is a common cause of rolling, perhaps even more popular than horse poop. I’ve seen countless dogs roll in these substances, but I’ve yet to meet a person whose response was, “Right on. That’s always fun.”

Karen B. London, PhD, is a Certified Applied Animal Behaviorist and Certified Professional Dog Trainer who specializes in working with dogs with serious behavioral problems, including aggression. She is the author of five books on canine training and behavior.